JP2023022724A - Image sensor and manufacturing method thereof - Google Patents

Abstract

To provide an image sensor which can be configured to be compact without needing pixel miniaturization to form a free curved shape and without needing a complicated control method to compensate variations between sensors while needing no advanced alignment of an optical system, and a manufacturing method thereof.SOLUTION: An image sensor includes a plurality of image sensor units 10 stacked on the top face of a thin film substrate 21 and having a light-receiving surface with a non-planar shape, each image sensor unit including: a thin film substrate 21; an organic photoelectric conversion element 22 including a pixel electrode 23, an organic film 24 and a counter electrode 25 which are stacked in this order on a lateral face of the thin film substrate 21 so as to form the light-receiving surface where light from the side of the thin film substrate 21 enters; and a readout circuit 26 for reading out signals from the organic photoelectric conversion element 22, the readout circuit being formed on the top face of the thin film substrate 21.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image pickup device used as various sensors and a manufacturing method thereof, and more particularly to an image pickup device operated by connecting a photoelectric conversion section provided on a substrate and a readout circuit and a manufacturing method thereof.

There is a demand for realization of a curved surface sensor having a non-planar light receiving part, such as a wide viewing angle sensor using a ball lens and a contact type sensor that is directly attached to the skin. Conventional sensors using ball lenses include a device that combines an optical fiber or optical waveguide with a planar sensor in the light receiving part (see Patent Documents 1 and 2 below), and a sensor that combines a plurality of planar sensors in the light receiving part of a ball lens. A device (see Patent Document 3 below) has been proposed.

Further, as for a contact sensor or the like, a method of forming a sensor on a flexible non-planar body by a transfer technique (see Patent Document 4 below) has been proposed.

Japanese Patent Application Laid-Open No. 2007-147706 JP 2017-130212 A JP 2017-017517 A Special Table No. 2012-515436

By the way, in the above-described wide-viewing-angle sensor or the like, when a complicated optical system such as an optical fiber or an optical waveguide is combined to form a light-receiving part, it is difficult to make the structure of the sensor compact. There is a problem that accurate alignment is also required. Moreover, when a light-receiving unit is configured by combining multiple planar sensors, in addition to the need to align the optical axes with high precision, a complicated control method is required to compensate for variations among the sensors. I had an issue that I needed to address.

In addition, when a sensor is formed on a flexible non-flat body by transfer technology, it is difficult to achieve high-precision alignment, and it is difficult to miniaturize pixels to form a free curved surface shape. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems. It is also an object of the present invention to provide an imaging device and a method of manufacturing the same, which can have a compact configuration without requiring a complicated control method for correcting variations between sensors.

In order to achieve the above object, the imaging device and the manufacturing method thereof according to the present invention are configured as follows.
That is, the first imaging device of the present invention is
a substrate;
an organic photoelectric conversion element formed by laminating a pixel electrode, an organic film and a counter electrode in this order on a side surface of the substrate so as to form a light-receiving surface on which light from the side of the substrate is incident;
a readout circuit for reading a signal from the organic photoelectric conversion element formed on the upper surface of the substrate;
an imaging element unit in which the light receiving surface is non-planar;
It is characterized by having

Next, a second image pickup device of the present invention is characterized in that, in the first image pickup device as described above, a plurality of the image pickup device units are laminated in the direction in which the upper surface faces. is.

Further, the third image pickup device of the present invention is
a substrate;
The pixel electrode, the organic film and the counter electrode are arranged perpendicular to the direction of incidence of the light in the region of the substrate on the light incidence side so as to form a light receiving surface on which the light from the side of the substrate is incident. An organic photoelectric conversion element laminated in this order in the direction of
a readout circuit formed in a predetermined region on the substrate and electrically connected to the pixel electrode for reading a signal from the organic photoelectric conversion element;
an imaging element unit in which the light receiving surface is non-planar;
It is characterized by having

Next, a fourth image sensor of the present invention is characterized in that, in the above-described third image sensor, a plurality of the image sensor units are stacked in the orthogonal direction.

Further, in any one of the imaging devices described above, the non-planar shape may be a cylindrical shape curved in the direction in which the substrate extends.
Further, the imaging device unit can be used for color image pickup by stacking respective imaging devices for R, G and B in a predetermined order.

Furthermore, it is preferable that the substrate is made of a plastic material.
Further, the light receiving surface has a semicircular peripheral shape,
A curved lamination-type imaging device obtained by laminating a plurality of the imaging device units having an overall arc shape, wherein the outer arc portions of the imaging device units are opened in the circumferential direction so as to be spaced apart from each other. On the other hand, it is possible to configure so as to have a partially spherical shape as a whole.

In addition, the first method for manufacturing an imaging device of the present invention includes:
A substrate is prepared in a desired curved shape,
a first step of forming a light-receiving portion having a light-receiving surface on which light from the side of the substrate is incident, by laminating a pixel electrode, an organic film and a counter electrode in this order on the side surface of the substrate;
a second step of forming a readout circuit for reading a signal from the organic photoelectric conversion element on the upper surface of the substrate;
A third step of stacking a plurality of imaging element units prepared by performing the first step and the second step in the direction in which the upper surface faces,
It is characterized by

Next, the second method for manufacturing an image pickup device of the present invention is as follows:
A substrate is prepared in a desired curved shape,
A light-receiving portion having a light-receiving surface on which light from the side of a substrate is incident is provided in a region on the light-incident side of the substrate, and a pixel electrode, an organic film, and a counter electrode are arranged perpendicular to the direction of incidence of the light. A first step of forming an organic photoelectric conversion element by stacking in this order in the direction of
a second step of forming a readout circuit for reading out a signal from the organic photoelectric conversion element, electrically connected to the pixel electrode, in a predetermined region on the substrate;
A third step of stacking a plurality of imaging element units created by performing the first step and the second step in the orthogonal direction,
It is characterized by

According to the image pickup device and the method for manufacturing the image pickup device of the present invention, no transfer technology is required for forming the light receiving surface, so that miniaturization of pixels and formation of a free curved surface shape can be facilitated. is possible. In addition, since no transfer technique for the light receiving surface is required, it is possible to eliminate the need for highly accurate alignment.

In addition, when forming a wide viewing angle sensor or the like, there is no need to configure the light receiving section by combining a complicated optical system such as an optical fiber or an optical waveguide, so the sensor configuration can be made compact. It is also possible to eliminate the need for advanced alignment.
Furthermore, since it is not required to configure the light receiving section by combining a plurality of planar sensors, it is not required to align the optical axes with high accuracy as in the prior art described above, and variations among the sensors can be corrected. There is no need to adopt a complicated control method for

Further, by stacking a plurality of imaging element units to form a stacked imaging element, a large-area sensor having a desired number of pixels can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a conceptual structure of an imaging device according to a first embodiment of the present invention ((a) is an external view showing the overall structure of a curved laminated imaging device; (b) is a curved laminated imaging device; (c) is a schematic diagram showing a part of an imaging element unit of a curved lamination type imaging element). FIG. 2 is a conceptual diagram showing the aspect of the curved surface shape of the curved laminated image pickup device according to the first embodiment of the present invention (the same applies to the second embodiment) ((a) shows an inverted S-shaped curved surface shape; FIG. (b) shows a spherical curved surface). FIG. 2 is a schematic diagram (Part 1) showing the method ((a) to (c)) of manufacturing the imaging device according to the first embodiment of the present invention; FIG. 2 is a schematic diagram (Part 2) showing the manufacturing method ((d) to (e)) of the imaging device according to the first embodiment of the present invention; FIG. 3 is a schematic diagram (Part 3) showing the manufacturing method ((f) to (h)) of the imaging device according to the first embodiment of the present invention; FIG. 10 is a schematic diagram (part 1) showing a method ((a) to (c)) of manufacturing an imaging device according to a modification of the first embodiment of the present invention; FIG. 10 is a schematic diagram (Part 2) showing a method ((d) to (f)) of manufacturing an imaging device according to a modification of the first embodiment of the present invention; FIG. 2 is a schematic diagram showing the conceptual structure of an imaging device according to a second embodiment of the present invention ((a) is an external view showing the overall structure of a curved laminated imaging device; (b) is a curved laminated imaging device; (c) is a schematic diagram showing a part of an imaging element unit of a curved lamination type imaging element). FIG. 10 is a schematic diagram showing a method ((a) to (f)) of manufacturing an imaging device according to a second embodiment of the present invention; When manufacturing a curved laminated image pickup device (having a cylindrical curved surface shape) according to an embodiment of the present invention (common to the first and second embodiments), an image pickup device unit is manufactured using a jig for lamination. It is a schematic diagram showing how to stack the. An example in which the curved layered imaging element (having a spherical curved surface shape) according to the embodiment of the present invention (common to the first and second embodiments) is applied to a curved surface sensor by arranging a ball lens inside. 1 is a schematic diagram showing the .

An image sensor and a method for manufacturing the same according to embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>
(Structure of image sensor)
FIG. 1(a) is an external view showing the overall structure of an imaging device (curved laminated imaging device) 10A according to the first embodiment, and FIG. 1(b) is a part of this curved laminated imaging device 10A. FIG. 1(c) is a conceptual diagram showing an enlarged configuration, and FIG. 1(c) shows a further enlarged view of a part of one imaging element unit 10 that constitutes this curved laminated imaging element 10A.

That is, as shown in FIG. 1(c), the imaging element unit 10 includes a thin film substrate 21 and a side surface of the thin film substrate 21 so as to form a light receiving surface on which light from the side of the thin film substrate 21 is incident. Furthermore, an organic photoelectric conversion element 22 in which a pixel electrode 23, an organic film 24 and a counter electrode 25 are laminated in this order, and an organic photoelectric conversion element (specifically, a pixel electrode) formed on the upper surface of the thin film substrate 21. 23), and a readout circuit 26 for reading the signal from 23), and the light receiving surface described above is configured to form a curved cylindrical surface shape.
By forming the thin film substrate 21 itself into the curved shape shown in FIG. 1A, the light receiving surface of the imaging element unit 10 can be formed into a predetermined curved shape.

The imaging element unit 10 can constitute an imaging element (sensor) by itself, but normally, as shown in FIG. 10 are combined (stacked on the upper surface of the thin film substrate 21) to form a color imaging unit of the imaging element unit 10. FIG.
Further, as shown in FIG. 1(a), a plurality of image pickup device units 10 (preferably color image pickup units) are arranged in a direction in which the upper surface faces (the depth direction in FIG. 1(a)) (a cylindrical unit). (designed as the number of pixels in the axial direction of ) are laminated to form a laminated body 29, thereby constructing the curved lamination type imaging device 10A.
Although not shown, input/output electrodes are formed on the thin film substrate 21 on the side opposite to the side on which the organic photoelectric conversion elements 22 are formed.

The pixel electrode 23, the readout circuit 26, and the input/output electrode are electrically connected in this order, and an external voltage is applied to the input/output electrode and the counter electrode 25. The charged charges are read out from the pixel electrodes 23 in the readout circuit 26, amplified as appropriate, and output to the outside from the input/output electrodes.
In FIG. 1(c), the size of the pixel electrode (vertical width of the pixel electrode 23 in FIG. 1(c)) is formed to be equal to the thickness of the thin film substrate 21. It may be formed smaller than 21.

As described above, the imaging device (curved laminated imaging device 10A) of the present embodiment is a curved sensor having a light receiving surface curved in one direction. , a pixel electrode 23, an organic film 24 and a counter electrode 25 are laminated in this order.

In the imaging element of this embodiment, since no transfer technique is required to form the light receiving surface, it is easy to miniaturize the pixels, and it is easy to form a free curved surface shape. high-precision alignment of the position becomes unnecessary.
Furthermore, even when forming a wide viewing angle sensor or the like, there is no need to configure a light receiving section by combining a complicated optical system such as an optical fiber or an optical waveguide, and the configuration of the sensor can be made compact. and no sophisticated alignment is required.
Furthermore, since there is no need to combine multiple planar sensors to form a light receiving unit, there is no need to perform highly accurate optical axis alignment, and there is no need to adopt a complicated control method for correcting variations between sensors. do not have.
Therefore, there are many advantages in easily manufacturing a curved surface sensor.

In addition, it is preferable that each imaging element unit 10 in the imaging element of the present embodiment constitutes a one-line sensor, and it is possible to configure such that pixels are extracted for each imaging element unit 10 .
As the thin film substrate 21, a thin plastic or a thin metal such as aluminum foil on which an insulating film is formed can be used.

By forming the thin film substrate 21 from a resin material such as plastic, it is possible to flexibly bond and position the imaging element units 10 . In other words, if the thin film substrate 21 is made of a hard material, the substrates are likely to come into contact with each other during lamination or position adjustment, causing damage, but this can be prevented.
Further, when a resin material such as plastic is used as the thin film substrate 21, in addition to the advantage that the film thickness can be easily controlled, it is also advantageous for mass production, and has a great advantage in terms of manufacturing cost.

Further, although the details will be described later, it is also possible to easily form a wide viewing angle sensor in combination with a ball lens.

The imaging element of this embodiment is characterized in that the organic photoelectric conversion element 22 is laminated on the side surface of the thin film substrate 21, unlike the imaging element of the second embodiment which will be described later. As a result of such a configuration, the size of the pixel can be adjusted by adjusting the thickness of the thin film substrate 21 .

Details of the curved laminated image sensor 10A according to the first embodiment will be further described below.
As described above, in the curved laminated image sensor 10A according to the present embodiment, the organic film 24 is used as the photoelectric conversion film, and the photoelectric conversion element is formed as the organic photoelectric conversion element 22 .
Also, the counter electrode 25 can be a common electrode that is electrically connected to all pixels. When the common electrode 25 is formed for all pixels, it can be configured by connecting only one end of the common electrode 25 to an external power supply or the like.

In addition, as the material of the organic photoelectric conversion film, a material having sensitivity to a predetermined wavelength can be applied to each imaging element unit 10. In this way, imaging element units 10 using different materials are arranged adjacent to each other. can be stacked together. For example, if an organic film material can be coated and formed, the image sensor units 10 to be stacked are arranged in the order of R, G, and B (or the order of R, B, and G, or the order of R, G, B, and G). A color image pickup device may be formed by using the arranged curved laminated image pickup device 10A.
Furthermore, a color filter may be combined with a photoelectric conversion film of an organic film. In this case, the color-coding of the color filters can be either line-by-line or pixel-by-pixel.

The readout circuit 26 is a circuit necessary for reading out a signal from the organic photoelectric conversion element 22, and includes a drive TFT, a selection TFT, a reset TFT, a load capacitor, etc. used in a conventional CMOS pixel circuit, as well as amplification. A semiconductor circuit manufacturing technique used in a conventional CMOS image sensor can be used for circuits, various arithmetic circuits, circuits for noise reduction, and the like.
Further, the signal readout circuit 26 can be configured by combining oxide semiconductor TFTs. A method for reading out signals from the organic photoelectric conversion element 22 may be compatible with various types of digital driving, or a normal method in which signals are amplified and read out for each pixel may be applied.

In addition, in the curved laminated image pickup device 10A according to the present embodiment, since a readout circuit and an arithmetic circuit are incorporated for each pixel, line sensor readout, single pixel readout, multiple pixel readout, etc. can be performed in units of each image pickup device 10A. The reading method can be freely set in .
Further, the arithmetic circuit and the like may be formed on the thin film substrate 21 using a transfer technique.

The thickness of the thin film substrate 21 can be freely selected according to the material, and is about several hundred nanometers to several hundred micrometers depending on, for example, the simplicity of the manufacturing process during lamination, the efficiency of light utilization, and the application of the device. can be freely selected within the range of

For example, when using a resin material that can be coated and formed into a film, it is possible to control the thickness of 1 μm or less by applying an extremely thin coating and curing, but it is also possible to form a thin film substrate with a film thickness of 100 μm or more. be.

FIGS. 2A and 2B show aspects of the curved surface shape of the curved laminated image pickup device in the image pickup device according to this embodiment. FIG. 2(a) shows an inverted S-shaped curved laminated imaging element 10B, and FIG. 2(b) shows a spherical curved laminated imaging element 10C.
As shown in FIGS. 2A and 2B, by changing the curved shape of the light-receiving surface and the method of stacking, it is possible to form curved stacked-type imaging elements having various desired shapes.
The timing of curved processing of the light-receiving surface can be set at a timing that facilitates manufacturing. It is preferable to carry out on the thin film substrate 21 because it is easy to manufacture.

In FIG. 2(a), a plurality of imaging element units 10 (left side figure) formed by forming layers on a thin film substrate 21 processed into an S shape are laminated to form a curved laminated imaging element 10B. (Right figure) is shown.
On the other hand, in FIG. 2(b), a plurality of imaging element units 10, which are formed by forming layers on a thin film substrate 21 processed into a semi-circular shape, are stacked to form a curved laminated imaging element 10C (left side). ) are formed, and furthermore, each image sensor unit 10 has a central axis (the central axis of the virtual sphere) as a supporting axis, and is opened in the circumferential direction so as to be spaced apart from each other, and is spherical as a whole ((1/4) 10C (the figure on the right side) is formed in a state of a spherical body).

(Manufacturing method of stacked imaging device)
Next, a method for manufacturing an imaging device according to this embodiment will be described with reference to FIGS. 3A to 3C.
First, a large-sized thin film substrate 21 is prepared, and a plurality of basic circuits (readout circuits and wiring electrodes) are simultaneously formed on the surface of this thin film substrate 21 . Arithmetic circuits and the like are also formed as necessary (FIG. 3A(a)).

Next, the thin film substrate 21 is cut for each basic circuit (FIG. 3A(b)). If it is difficult to form (pattern) the electrodes and the like up to the edge of the thin film substrate 21, the edge of the thin film substrate 21 is cut so that the edge of the pattern such as the electrode is positioned at the edge of the thin film substrate 21. Remove.
The thin film substrates 21 obtained by cutting are arranged in parallel so that the light receiving surfaces are located on the same plane (FIG. 3A(c)), and the pixel electrodes 23 are formed on the light receiving surfaces of the thin film substrates 21 by a vapor deposition method. , a sputtering method, a coating method, or the like (patterning is also performed at the same time)) (FIG. 3B(d)).

Next, an organic film 24 (an organic photoelectric conversion film, a blocking layer, or the like) is formed on the pixel electrode 23 of each thin film substrate 21 using an arbitrary film formation method such as a vapor deposition method or a coating method (FIG. 3B ( e)). As shown in the figure, when the photoelectric conversion film materials of three colors of RGB are separately painted, an organic film 24 (organic film (B) 24B, organic film (G) 24G, organic film (R) 24R) is formed for each color. .

An adhesive layer 28 is applied to the surface side of each thin film substrate 21 (FIG. 3C(f)), and the thin film substrates 21 for each color are laminated in a desired order as shown in FIG. 1(b). They are pasted together (FIG. 3C(g)). After that, the adhesive layer 28 is subjected to curing treatment as necessary.
Finally, as shown in FIG. 3C(h), a common counter electrode 25 is formed on the organic films 24 (organic film (B) 24B, organic film (G) 24G, organic film (R) 24R) of the entire thin film substrate 21. is formed using any film forming method such as a vapor deposition method, a sputtering method, or a coating method.

4A and 4B can be used instead of the method shown in FIGS. 3A to 3C as the method for manufacturing the imaging device according to the embodiment.
That is, in the method of the embodiment described above, after forming the organic films 24B, 24G, and 24R as shown in FIG. 3B(e), each thin film substrate 21 is attached as shown in FIG. 3C(g). After that, as shown in FIG. 3C(h), a counter electrode 25 is formed. When using an apparatus capable of forming a film according to a curved surface, the thin film substrates 121 are bonded together. It is also possible to use a method of forming the organic film 124 or the like later.

That is, in the series of manufacturing steps shown in FIGS. 4A(a) to 4B(f), as shown in FIG. As shown in FIG. 4B(e), the pixel electrodes 123 may be formed on the light receiving surfaces of the thin film substrates 121, and the organic film 124 may be formed on the pixel electrodes 123 as shown in FIG. 4B(e). 4A(a) to 4B(f), the other steps are the same as the method of the above-described embodiment shown in FIGS. 3A to 3C, so description thereof is omitted. do. 4A(a) to 4B(f), the reference numerals of the members corresponding to the members shown in FIGS. 3A(a) to 3C(h) are 100 is added to the reference numerals of the members shown in h).

<Second embodiment>
(Structure of image sensor)
FIG. 5(a) is an external view showing the overall structure of an imaging device (curved laminated imaging device) 210A according to the second embodiment, and FIG. 5(b) shows a part of this curved laminated imaging device 210A. FIG. 5C is a conceptual diagram showing an enlarged configuration, and FIG. 5C shows a further enlarged view of one imaging element unit 210 that constitutes the curved laminated imaging element 210A.

That is, as shown in FIG. 5(c), the imaging device unit 210 includes a thin film substrate 221 and a light receiving surface on which light from the side of the thin film substrate 221 is incident. An organic photoelectric conversion element 222 formed by laminating a pixel electrode 223, an organic film 224 and a counter electrode 225 in this order at the light incident side end, and an organic photoelectric conversion element 222 formed on the upper surface of the thin film substrate 221 ( Specifically, it includes a readout circuit 226 for reading out signals from the pixel electrodes 223), and is configured so that the light receiving surfaces of the image sensor units 210 described above form the same curved cylindrical surface shape. It is

The image pickup element unit 210 can constitute a curved image pickup element (sensor) by itself, but usually, for example, image pickup element units for R, G and B are combined in a predetermined order. (stacked in a predetermined order in the upper surface direction of the image pickup device unit 210) to form a color image pickup unit of the image pickup device unit 210. FIG.
Further, as shown in FIG. 5(a), a plurality of color imaging units (the number corresponding to the number of pixels in the axial direction of the cylinder) of the imaging device unit 210 are laminated in the upper surface direction to form a laminate 229. are formed to construct the curved laminated imaging element 210A.
An input/output electrode 227 is formed on the thin film substrate 221 on the opposite side of the organic photoelectric conversion element 222 (light incident side).

The pixel electrode 223, the readout circuit 226, and the input/output electrode 227 are electrically connected in this order, and an external voltage is applied between the pixel electrode 223 and the counter electrode 225 via the input/output electrode 227 and the readout circuit 226. , and the detection signal (imaging signal) of the organic photoelectric conversion element 222 read by the readout circuit 226 is output from the input/output electrode 227 to the outside.

As described above, the imaging device 210 of this embodiment is a curved sensor having a light receiving surface curved in one direction. 225 are laminated in this order, and an organic photoelectric conversion element 222 is provided.

In the imaging element of the present embodiment, since no transfer technology is required to form the light receiving surface, it is easy to miniaturize the pixels, easily form a free curved surface shape, and increase the height of the imaging element. Accurate alignment becomes unnecessary.
Furthermore, even when forming a wide viewing angle sensor or the like, there is no need to configure a light receiving section by combining a complicated optical system such as an optical fiber or an optical waveguide, and the configuration of the sensor can be made compact. and no sophisticated alignment is required.
Furthermore, since there is no need to combine multiple planar sensors to form a light receiving unit, there is no need to perform highly accurate optical axis alignment, and there is no need to adopt a complicated control method for correcting variations between sensors. do not have.
Therefore, it has many advantages in easy production.

Further, it is preferable that each of the imaging element units 210 in the curved laminated imaging element 210A of the present embodiment constitutes one line sensor, and it is possible to configure such that pixels are extracted for each imaging element unit 210. .
As the thin film substrate 221, a thin plastic or a thin metal such as aluminum foil on which an insulating film is formed can be used.

By forming the thin film substrate 221 from plastic, it is possible to flexibly bond and adjust the positions of the imaging element units 210 . In other words, when the thin film substrate 221 is formed of a hard material, damage is likely to occur due to contact between the substrates during lamination or position adjustment, but this can be prevented.
Further, when a resin material such as plastic is used as the thin film substrate 221, it has the advantage of being easy to control the film thickness, and is also advantageous in terms of mass production and manufacturing cost.

Further, although details will be described later, it is also possible to easily form a wide viewing angle sensor by combining with a ball lens, as in the first embodiment.

In addition, unlike the image pickup device of the first embodiment, the image pickup device of this embodiment is formed by stacking the organic photoelectric conversion element 222 on the upper surface of the thin film substrate 221 (the surface on which the readout circuit 226 is formed). It is characterized by the fact that
As a result of such a configuration, the size of the pixels does not depend on the thickness of the thin film substrate 221. Therefore, compared with the image pickup device of the first embodiment, the pixels can be arranged at a higher density and the pixel electrodes can be reduced. By increasing the size, it is possible to sufficiently absorb the incident light, so that it has the advantage of high light receiving efficiency. Furthermore, since all the stacking directions in each manufacturing process are the upward direction of the thin film substrate 21, there is an advantage that the imaging device can be easily manufactured as compared with the imaging device of the first embodiment.
In addition, in the imaging element unit 210 of the curved laminated imaging element 210A of the present embodiment, the light receiving area of the organic photoelectric conversion element 222 is (the length of the side along the thin film substrate 221 at the end surface of the pixel electrode 223 on the light receiving surface side thickness) and (thickness of organic film 224).

In addition, since the imaging device of the present embodiment is a so-called side illumination type imaging device, it is not necessary to form the counter electrode 225 transparently. Rather, the pixel electrode 223 and the counter electrode 225 are preferably opaque because color mixing between adjacent pixels in the stacking direction (perpendicular direction) of the pixel electrode 223 and the counter electrode 225 is prevented. Therefore, it is possible to apply various opaque electrode materials, and it is also possible to select a material that causes less damage to the organic film 224 .

In addition, in the imaging device of this embodiment, the pixel electrode 223 can have a large depth with respect to the light-receiving surface, and the organic film 224 does not have wavelength dependence in the depth direction. All of them can be absorbed and used, and good wavelength characteristics according to the material can be obtained.

Details of the imaging device (curved laminated imaging device) 210A according to the second embodiment will be further described below.
As described above, in the curved laminated image sensor 210A according to this embodiment, the organic film 224 is used as the photoelectric conversion film, and the photoelectric conversion element is formed as the organic photoelectric conversion element 222 .
Also, the counter electrode 225 can be a common electrode that is electrically connected to all pixels. When the common electrode 225 is formed for all the pixels, it can be configured by connecting only one end of the common electrode 225 to an external power supply or the like.
Note that not only the pixel electrode 223 but also the counter electrode 225 can be connected to the readout circuit 226 .

Further, as the material of the organic photoelectric conversion film, a material having sensitivity to a predetermined wavelength can be applied for each imaging element unit 210 . In this way, the imaging element units 210 using different materials can be stacked so as to be adjacent to each other. For example, when an organic film material can be coated and formed, the stacked imaging element units 210 are arranged in the order of R, G, and B (or the order of R, B, G, or the order of R, G, B, G, etc.). A color image pickup device may be formed by forming the curved laminated image pickup device 210A.
Furthermore, the color filter and the photoelectric conversion film of the organic film 224 may be combined. In this case, the color-coding of the color filters can be either line-by-line or pixel-by-pixel.
Also, if the organic film 224 can be formed by coating, it is possible to use different materials in one imaging element unit 210, for example, to separately paint RGB.

The readout circuit 226 is a circuit necessary for reading out a signal from the organic photoelectric conversion element 222, and includes a drive TFT, a selection TFT, a reset TFT, a load capacitor, etc. used in a conventional CMOS pixel circuit, as well as amplification. A semiconductor circuit manufacturing technique used in a conventional CMOS image sensor can be used for circuits, various arithmetic circuits, circuits for noise reduction, and the like.
Further, the signal readout circuit 226 can be configured by combining oxide semiconductor TFTs. As a readout method of the signal from the organic photoelectric conversion element 222, a method corresponding to various digital driving may be used, or a normal method of amplifying and reading out for each pixel may be applied.

In addition, in the curved laminated image pickup device 210A according to the present embodiment, since a readout circuit and an arithmetic circuit are incorporated for each pixel, line sensor readout, single pixel readout, multi-pixel readout, etc., can be performed in each image pickup device unit 210. The reading method can be freely set in .
Further, the arithmetic circuit and the like may be formed on the thin film substrate 221 using a transfer technique.

The thickness of the thin film substrate 221 can be freely selected according to the material, and is about several hundred nm to several hundred μm depending on, for example, the simplicity of the manufacturing process during lamination, the efficiency of light utilization, and the application of the device. can be freely selected within the range of

For example, when using a resin material that can be applied to form a film, it is possible to control the thickness of 1 μm or less by applying an extremely thin film and then curing it. is.

2(a) and 2(b) are conceptual diagrams showing aspects of the curved surface shape of the curved laminated image pickup device in the image pickup device according to the present embodiment. The description is the same as in the case of the first embodiment, so a repeated description of the case of the second embodiment will be omitted.

(Manufacturing method of stacked imaging device)
Next, a method for manufacturing an imaging device according to this embodiment will be described with reference to FIGS.
First, a thin film substrate 221 having a predetermined size is prepared (FIG. 6(a)). formed (FIG. 6(b)).

Next, an organic film 224 is formed on the pixel electrodes 223 formed on the light incident side of the thin film substrate 221 (FIG. 6(c)). For forming the organic film 224, any of a dry method such as a vapor deposition method, a wet method such as a spin coating method and an ink jet method can be used.

Subsequently, a counter electrode 225 is formed on the organic film 224 (which can be common to all the organic films 224 arranged on the same plane) (FIG. 6D). Any method such as a vapor deposition method, a sputtering method, or a coating method can be used as this forming method. At this time, if the input/output electrodes 227 cannot be formed to the ends of the thin film substrate 221, the ends of the thin film substrate 221 are cut so that the input/output electrodes 227 are formed at the ends of the thin film substrate 221. Auxiliary processing is performed so that it is distributed.

Finally, an adhesive is applied to a predetermined position on the surface of each thin film substrate 221 to form an adhesive layer 228 (FIG. 6(e)). 228, and by repeating this bonding operation, a laminated body 229 is formed to complete the curved laminated imaging device 210A (FIG. 6(f)).

(Additional matters related to the embodiment)
Other considerations ((a) to (i)) for each of the above-described embodiments will be described below in an enumerated form.
(a) Since it is difficult to pattern the electrodes on the light-receiving part by a normal method, it is preferable to pattern the electrodes using a shadow mask or the like when forming the electrodes. Instead of the patterning method using a shadow mask, it is also possible to use, for example, a method of forming an opening using a thin wire as a mask and patterning the electrode.

(b) The formation of the organic films 24, 224 on the imaging element units 10, 210 is preferably performed at once for each color (for example, R, G, B) from the viewpoint of increasing manufacturing accuracy. It is recommended to form the organic films 24 and 224 for the same color for all the pixels of one line of the imaging device units 10 and 210 .
(c) When color filters are used, <1> Formation of pixel electrodes 23 and 223, <2> Formation of organic films 24 and 224, <3> Formation of color filters (formed for each color) is preferable, and it is preferable that all one line has the same color as in the case of the organic films 24 and 224), <4> Bonding of the imaging element units 10 and 210, <5> Formation of the counter electrodes 25 and 225, It is efficient to follow the procedure of

(d) When the organic films 24 and 224 are not required to be color-coded, such as for capturing a monochrome image, <1> formation of the pixel electrodes 23 and 223, and <2> lamination of the imaging element units 10 and 210 , <3> Formation of the organic films 24 and 224, and <4> Formation of the counter electrodes 25 and 225 are effective.

(e) In the process of laminating the imaging element units 10 and 210, as described above, the adhesive layers 28 and 228 are formed on the thin film substrates 21 and 221, and the imaging element units 10 and 210 are laminated. It is effective to laminate them by bonding them together. In this case, in order to improve lamination accuracy, it is necessary to perform the adhesion process while aligning the imaging element units 10 and 210 . For this reason, as shown in FIG. 7, a stacking jig 350 having a curved inner wall surface matching the outer shape of the image sensor unit 310 is used, and the image sensor units 310 are sequentially stacked on the inner wall surface of the stacking jig 350. It is preferable that the curved lamination type imaging device 310A is manufactured by arranging them so as to be aligned with each other and sequentially pasting them together.

(f) The readout circuits 26 and 226, the input/output electrodes 227, and the like can be formed by general methods used in semiconductor processes, and there are no particular restrictions on the materials and manufacturing methods used. For example, as electrodes, it is possible to apply general conductive materials such as metals and organic conductive films. It can be adopted as appropriate.

(g) The patterning of the electrodes can be performed simultaneously with the film formation by a printing method or the like, in addition to the photolithography method.
(h) It is possible to form an insulating film between the wirings as necessary when crossing various wirings. Applicable. The same applies to the etching process of the insulating film and the like.

(i) In the image pickup device of the present embodiment, as described with reference to FIG. 2B, the curved laminated image pickup device 10C having a spherical shape as a whole (or a part of a spherical shape) can be easily formed.
That is, a plurality of imaging element units 10, which are prepared by forming layers on a thin film substrate 21 processed into a semicircular peripheral shape, are laminated to form a curved lamination type as shown in the left diagram of FIG. 2(b). The imaging element 10C is formed, and further, the imaging element units 10 are opened in the circumferential direction with the central axis (the central axis of the phantom sphere) as the support axis so as to be spaced apart from each other, and the right side of FIG. A curved lamination type imaging device 10C as shown in the figure can be formed.
Furthermore, as shown in FIG. 8, a ball lens 440 is arranged in the curved laminated imaging element 410C, and this ball lens 440 is held by a transparent support 442 so as to be positioned at the center of the curved laminated imaging element 410C. (further surrounded by a plurality of imaging element units 410), it is possible to easily form an ultra-wide viewing angle sensor.

The imaging device and the manufacturing method thereof according to the present invention are not limited to the above-described embodiments, and other various modifications are possible. For example, it is possible to use an imaging element unit to which a photoelectric conversion layer sensitive to ultraviolet rays or infrared rays is applied.
In addition, in the second embodiment, the readout circuit is formed in the region where the organic photoelectric conversion element is not formed. The readout circuit may be formed in a region where the readout circuit is covered with an organic film or a counter electrode.
In addition, the method for manufacturing the stacked imaging device of the present invention is not limited to the order of the steps according to the above-described embodiment. Either of the manufacturing processes (second process) may be performed first, and any arbitrary steps of the first process and any arbitrary steps of the second process may be performed first (simultaneously may be) may be performed.

10, 210, 310, 410 Imaging device unit 10A, 10B, 10C, 210A, 310A, 410C Curved laminated imaging device 21, 121, 221 Thin film substrate 22, 222 Organic photoelectric conversion device 23, 123, 223 Pixel electrode 24, 24B , 24G, 24R, 124, 224 organic film 25, 125, 225 counter electrode 26, 126, 226 readout circuit 227 input/output electrode 28, 128, 228 adhesive layer 29, 129, 229 laminate 350 lamination jig 440 ball lens 442 transparent support

Claims (10)

a substrate;
an organic photoelectric conversion element formed by laminating a pixel electrode, an organic film and a counter electrode in this order on a side surface of the substrate so as to form a light-receiving surface on which light from the side of the substrate is incident;
a readout circuit for reading a signal from the organic photoelectric conversion element formed on the upper surface of the substrate;
an imaging element unit in which the light receiving surface is non-planar;
An imaging device characterized by having: 2. The image pickup device according to claim 1, wherein a plurality of said image pickup device units are laminated in the direction in which said upper surface faces. a substrate;
The pixel electrode, the organic film and the counter electrode are arranged perpendicular to the direction of incidence of the light in the region of the substrate on the light incidence side so as to form a light receiving surface on which the light from the side of the substrate is incident. An organic photoelectric conversion element laminated in this order in the direction of
a readout circuit formed in a predetermined region on the substrate and electrically connected to the pixel electrode for reading a signal from the organic photoelectric conversion element;
an imaging element unit in which the light receiving surface is non-planar;
An imaging device characterized by having: 4. The imaging device according to claim 3, wherein a plurality of said imaging device units are laminated in said orthogonal direction. 5. The image pickup device according to claim 1, wherein the non-planar shape is a cylindrical shape curved in the direction in which the substrate extends. 6. The imaging element unit is formed by stacking imaging elements for R, G, and B in a predetermined order for capturing a color image. The imaging device according to . 7. The imaging device according to claim 1, wherein said substrate is made of a plastic material. The light receiving surface has a semicircular peripheral shape,
A curved lamination-type imaging device obtained by laminating a plurality of the imaging device units having an overall arc shape, wherein the outer arc portions of the imaging device units are opened in the circumferential direction so as to be spaced apart from each other. 8. The imaging device according to claim 5, or claim 6 or 7, wherein claim 5 is quoted, wherein the image pickup device is partially spherical as a whole. A substrate is prepared in a desired curved shape,
A first step of forming an organic photoelectric conversion element by laminating a light-receiving portion having a light-receiving surface on which light from the side of a substrate is incident, a pixel electrode, an organic film, and a counter electrode in this order on the side surface of the substrate. and,
a second step of forming a readout circuit for reading a signal from the organic photoelectric conversion element on the upper surface of the substrate;
A third step of stacking a plurality of imaging element units prepared by performing the first step and the second step in the direction in which the upper surface faces,
A method for manufacturing an imaging device, characterized by: A substrate is prepared in a desired curved shape,
A light-receiving portion having a light-receiving surface on which light from the side of a substrate is incident is provided in a region on the light-incident side of the substrate, and a pixel electrode, an organic film, and a counter electrode are arranged perpendicular to the direction of incidence of the light. A first step of forming an organic photoelectric conversion element by stacking in this order in the direction of
a second step of forming a readout circuit for reading out a signal from the organic photoelectric conversion element, electrically connected to the pixel electrode, in a predetermined region on the substrate;
A third step of stacking a plurality of imaging element units created by performing the first step and the second step in the orthogonal direction,
A method for manufacturing an imaging device, characterized by:

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